The invention relates generally to insecticides and more particularly to a topical insecticide, such as one suitable to use on house pets such as cats and dogs.
The infestation of animals with fleas, ticks, flies and the like is highly undesirable. Accordingly, it has become common to administer both topical and internal insecticides to livestock and pets. Topical applications can be desirable, in that many insecticides are acceptably safe when used topically, but not when used internally.
Various topical insecticides have drawbacks. Some require a large volume to be applied to the animal. This can cause considerable mess and can lead to an unpleasant smell. Also, when the animal is a house pet, there is a further complication in that the insecticide should be safe for human contact. It should also not lead to staining of furniture, carpeting and the like. Finally, even if safe, topical insecticides for house pets should not be irritating or lead to rashes, hair loss or exhibit other unpleasant side effects.
Accordingly, it is desirable to provide an improved topical insecticide, which overcomes drawbacks of the prior art.
Generally speaking, in accordance with the invention, a topical insecticide is provided which can be safe to use and avoids many common deleterious side effects of conventional topical insecticides. In one preferred embodiment of the invention, the active ingredient of the insecticide formulation is an amine derivative, having a nitro-methylene group, a nitroamino group or a cyanoamino group, which can be formulated to have low toxicity and excellent insecticidal activity. Active ingredients of insecticides and their method of formation in accordance with the preferred embodiments of the invention are discussed in U.S. Pat. Nos. 5,532,365 and 5,434,181, the contents of which are incorporated herein by reference. One particularly suitable insecticide is 1-{(tetrahydro-3-furanyl)methyl}-2-nitro-3-methylguanidine (dinotefuran). Dinotefuran is an aldulticide that will kill adult fleas.
In one preferred embodiment of the invention, the active portion of the insecticide formulation comprises (tetrahydro-3-furanyl)methylamine derivatives of following formula (1). 
Active ingredients and insecticides in accordance with preferred embodiments of the invention are generally available as crystals and solids. Therefore, they need to be dissolved or otherwise put into a liquid form for use as topical spot products on animals. Topical spot products are more advantageous if the amount of liquid applied can be minimized. This must be balanced with the need for appropriate dosage to achieve the desired insecticidal effect. Therefore, it is desirable to use a solvent that will allow the solubilization of a high concentration of insecticide.
It has been determined that the insecticidal materials of the invention are advantageously dissolved in alcohols, but to relatively low concentrations. Phenyl methanol, is an alcohol, also known as benzyl alcohol, and is a liquid, somewhat soluble in water. It is routinely used in perfumes, flavors, photographi-c developers, dyes, films and inks and has other uses. It was surprisingly discovered that a relatively high concentration of the insecticide can be solubilized in phenyl methanol.
In one aspect of the current invention, the compound is dissolved in solvent to a concentration range of 2-20%, more preferably 4-17% and most preferably about 8 to 14%, with 12.5% as a preferred example. All percentages, unless otherwise evident, are on a weight basis.
In another preferred embodiment of the invention, the preferred solvent component comprises a mixture comprising water, ethyl lactate and ethanol, wherein the final concentration of ethyl lactate ranges from 5-20% and the final concentration of ethanol ranges from 30-45%, more preferably 7-15% ethyl lactate and 35-43% ethanol and most preferable a final concentration of 10% ethyl lactate and 40% ethanol. The remainder can be water. Isopropanol can also be added to ethanol to improve solubility.
Accordingly, it is an object of the invention to provide an improved topical insecticide, which overcomes drawbacks of the prior art.
The novel (tetrahydro-3-furanyl)methylamine derivatives of the formula (1) have an excellent insecticidal activity even in the absence of a pyridylmethyl group or a thiazolylmethyl group in their molecular structure. According to the present invention, there are provided (tetrahydro-3-furanyl)methylamine derivatives represented by formula (1), where X1, X2, X3, X4, X5, X6 and X7 represent each a hydrogen atom or an alkyl group having from 1 to 4 carbon atoms; R1 represents a hydrogen atom, an alkyl group having from 1 to 5 carbon atoms, an alkenyl group having 3 carbon atoms, a benzyl group, an alkoxyalkyl group having from 2 to 4 carbon atoms (in its whole group), an alkyloxycarbonyl group having from 1 to 3 carbon atoms, a phenoxy carbonyl group, an alkylcarbonyl group having from 1 to 6 carbon atoms, an alkenylcarbonyl group having from 2 to 3 carbon atoms, a cycloalkylcarbonyl group having from 3 to 6 carbon atoms, a benzoyl group, a benzoyl group substituted by alkyl group(s) having from 1 to 4 carbon atoms, a benzoyl group substituted by halogen atom(s), a 2-furanylcarbonyl group or an N,N-dimethylcarbamoyl group; R2 represents a hydrogen atom, an amino group, a methyl group, an alkylamino group having from 1 to 5 carbon atoms, a di-substituted alkylamino group having from 2 to 5 carbon atoms (in its whole group), a 1-pyrrolidinyl group, an alkenylamino group having 3 carbon atoms, an alkynylamino group having 3 carbon atoms, a methoxyamino group, an alkoxyalkylamino group having from 2 to 4 carbon atoms (in its whole group), a methylthio group or xe2x80x94N(Y1)Y2 (where Y1 represents an alkyloxycarbonyl group having from 1 to 3 carbon atoms, a phenoxycarbonyl group, an alkylcarbonyl group having from 1 to 6 carbon atoms, an alkenylcarbonyl group having from 2 to 3 carbon atoms, a cycloalkylcarbonyl group having from 3 to 6 carbon atoms, a benzoyl group, a benzoyl group substituted by alkyl group(s) having from 1 to 4 carbon atoms, a benzoyl group substituted by halogen atom(s), a 2-furanylcarbonyl group, an N,N-dimethylcarbamoyl group, a (tetrahydro-3-furanyl)methyl group or a benzyl group, and Y2 represents a hydrogen atom or an alkyl group having from 1 to 5 carbon atoms); and Z represents xe2x95x90Nxe2x80x94NO2, xe2x95x90CHxe2x80x94NO2 or xe2x95x90Nxe2x80x94CN; insecticides containing the derivatives as an effective ingredient; and intermediates for producing the compounds of the formula (1) represented by a formula (2): 
where X1, X2, X3, X4, X5, X6 and X7 represent each a hydrogen atom or an alkyl group having from 1 to 4 carbon atoms; R10 represents an alkyl group having from 1 to 5 carbon atoms or a benzyl group; and R11 represents an alkyl group having from 1 to 5 carbon atoms or a benzyl group.
The novel (tetrahydro-3-furanyl)methylamine derivatives of the formula (1) and formula (2) according to the invention are excellent compounds having a high insecticidal power and broad insecticidal spectrum. Further, agricultural chemicals containing the novel (tetrahydro-3-furanyl) methylamine derivatives of the formula (1) and (2) according to the invention have outstanding characteristics as insecticides and hence are useful.
Specific examples of the alkyl group for X1, X2, X3, X4, X5, X6 and X7 in the above formulae (1) and (2) include a methyl group, an ethyl group, an n-propyl group, an iso-propyl group, a tert-butyl group, and the like, preferably a methyl group.
Specific examples of the alkyl group for R1 include a methyl group, an ethyl group, an n-propyl group, an iso-propyl group, an n-butyl group, an iso-butyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, and the like.
Specific examples of the alkenyl group for R1 include a 1-propenyl group, a 2-propenyl group, and the like.
Specific examples of the alkoxyalkyl group for R1 include a methoxymethyl group, an ethoxymethyl group, an n-propoxymethyl group, an iso-propoxymethyl group, a methoxyethyl group, an ethoxyethyl group, and the like.
Specific examples of the alkyloxycarbonyl group for R1 include a methyloxycarbonyl group, an ethyloxycarbonyl group, an n-propyloxycarbonyl group, an iso-propyloxycarbonyl group, and the like.
Specific examples of the alkylcarbonyl group for R1 include a methylcarbonyl group, an ethylcarbonyl group, an n-propylcarbonyl group, an iso-propylcarbonyl group, an n-butylcarbonyl group, an iso-butylcarbonyl group, a sec-butylcarbonyl group, a tert-butylcarbonyl group, an n-pentylcarbonyl group, an n-hexylcarbonyl group, and the like.
Specific examples of the alkenylcarbonyl group for R1 include a vinylcarbonyl group, a 1-methylvinylcarbonyl group, and the like.
Specific examples of the cycloalkylcarbonyl group for R1 include a cyclopropylcarbonyl group, a cyclobutylcarbonyl group, a cyclopentylcarbonyl group, a cyclohexylcarbonyl group, and the like.
Specific examples of the benzoyl group substituted by alkyl group(s) for R1 include a 2-methylbenzoyl group, a 3-methylbenzoyl group, a 4-methylbenzoyl group, a 4-tert-butylbenzoyl group, and the like.
Specific examples of the benzoyl group substituted by halogen atom(s) for R1 include a 2-chlorobenzoyl group, a 3-chlorobenzoyl group, a 4-chlorobenzoyl group, a 3,4-dichloro-benzoyl group, a 4-fluorobenzoyl group, and the like.
Although R1 can take various substituents as described above, it is preferably a hydrogen atom, an alkylcarbonyl group having from 1 to 4 carbon atoms or a cyclopropylcarbonyl group.
Specific examples of the alkylamino group for R2 include a methylamino group, an ethylamino group, an n-propyl-amino group, an iso-propylamino group, an n-butylamino group, an iso-butylamino group, a sec-butylamino group, a tert-butylamino group, an n-pentylamino group, and the like, preferably a methylamino group.
Specific examples of the di-substituted alkylamino group for R2 include a dimethylamino group, a diethylamino group, an N-methyl-N-ethylamino group, an N-methyl-N-n-propylamino group, an N-methyl-N-n-butylamino group, and the like, preferably a dimethylamino group.
Specific examples of the alkenylamino group for R2 include a 1-propenylamino group, a 2-propenylamino group, and the like.
Specific examples of the alkynylamino group for R2 include a propargylamino group, and the like.
Specific examples of the alkoxyalkylamino group for R2 include a methoxymethylamino group, an ethoxymethylamino group, an n-propoxymethylamino group, an iso-propoxymethylamino group, a methoxyethylamino group, an ethoxyethylamino group, and the like.
Specific examples of the alkyloxycarbonyl group denoted by Y1 for R2 include a methyloxycarbonyl group, an ethyloxy-carbonyl group, an n-propyloxycarbonyl group, an iso-propyloxy-carbonyl group, and the like.
Specific examples of the alkylcarbonyl group denoted by Y1 for R2 include a methylcarbonyl group, an ethylcarbonyl group, an n-propylcarbonyl group, an iso-propylcarbonyl group, an n-butylcarbonyl group, an isobutylcarbonyl group, a sec-butyl-carbonyl group, a tertbutylcarbonyl group, an n-pentylcarbonyl group, an n-hexylcarbonyl group, and the like, preferably a methylcarbonyl group, an ethylcarbonyl group, an n-propylcarbonyl group, an iso-propylcarbonyl group, an n-butylcarbonyl group, an iso-butylcarbonyl group, a sec-butylcarbonyl group and a tert-butylcarbonyl group.
Specific examples of the alkenylcarbonyl group denoted by Y1 for R2 include a vinylcarbonyl group, a 1-methyl-vinylcarbonyl group, and the like.
Specific examples of the cycloalkylcarbonyl group denoted by Y1 for R2 include a cyclopropylcarbonyl group, a cyclobutylcarbonyl group, a cyclopentylcarbonyl group, a cyclo-hexylcarbonyl group, and the like, preferably a cyclopropyl-carbonyl group.
Specific examples of the benzoyl group substituted byalkyl group(s) denoted by Y1 for R2 include a 2-methylbenzoyl group, a 3-methylbenzoyl group, a 4-methylbenzoyl group, a 4-tert-butylbenzoyl group, and the like.
Specific examples of the benzoyl group substituted by halogen atom(s) denoted by Y1 for R2 include a 2-chlorobenzoyl group, a 3-chlorobenzoyl group, a 4-chlorobenzoyl group, a 3,4-dichlorobenzoyl group, a 4-fluoro benzoyl group, and the like.
Specific examples of the alkyl group denoted by Y2 for R2 include a methyl group, an ethyl group, an n-propyl group, an iso-propyl group, an n-butyl group, an iso-butyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, and the like, preferably a methyl group.
In the formula (1), compounds in which R1 and Y1 are concurrently an alkylcarbonyl group having from 1 to 4 carbon atoms or a cyclopropylcarbonyl group are preferred from the viewpoint of both insecticidal activity and production method.
In the development of a formulation for use on animals, there are several parameters that must be considered. These are:
(a) Concentration high enough to minimize the volume of the topical applied to the animal (one would not want to put 20 ml, e.g., onto a small cat).
(b) The formulation should be stable for one month at 130xc2x0 F., 100xc2x0 F., 40xc2x0 F., room temperature and 0xc2x0 F. This helps ensure that the formulation remains stable under the conditions that it could meet in commerce.
(c) Safe to use on the animalxe2x80x94particularly non-irritating since the product is applied to the skin. Also safe if ingested by the animal; ingestion can occur when cats groom themselves.
(d) Safe to use by the consumer.
(e) Efficacious in usexe2x80x94should kill greater than 90% of the fleas up to 28 days.
(f) Efficacy would be reduced if crystallization occurred in the package.
(g) Needs to be aesthetically pleasingxe2x80x94xe2x80x9cno oily dropxe2x80x9d on the animal when applied.
(h) Fast drying to reduce the chance of the animal shaking off the liquid thereby reducing efficacy.
(i) Microbiologically stable.
The above-referenced patents recognize different possible solvents, but do not provide information on how to formulate insecticide in a non-irritating manner. No examples were given in which the compounds were used on animals. Additionally, in all of the examples given the compounds were dissolved into solvents that are undesirable to use on animals. Specifically, acetone, used in all but one of the examples, is very irritating by both inhalation and skin contact, due to de-fatting action on skin and mucous membranes. It is also very irritating to the eyes. Accordingly, there is a need to develop a different solvent for these compounds that can be used on animals. The present formulation satisfies the parameters detailed above.
It has been found that when the solvent comprises phenyl methanol or a combination of ethyl lactate and ethanol, higher concentrations of active ingredient can be incorporated. In one aspect of the current invention, the active compound is dissolved in solvent to a concentration range of 2-20%, more preferably 4-17% and most preferably about 8 to 14%, with 12.5% as a preferred example. All percentages, unless otherwise evident, are on a weight basis.
In another preferred embodiment of the invention, the preferred solvent component comprises a mixture comprising water, ethyl lactate and ethanol, wherein the final concentration of ethyl lactate ranges from 5-20% and the final concentration of ethanol ranges from 30-45%, more preferably 7-15% ethyl lactate and 35-43% ethanol and most preferable a final concentration of 10% ethyl lactate and 40% ethanol. The remainder can be water. Isopropanol can also be added to ethanol to improve solubility.
In one embodiment of the invention, the preferred solvent component comprises a mixture comprising water and ethanol at a concentration range of 50-80% ethanol, more preferably 65-75% ethanol and most preferably about 69-71% ethanol, with a preferred example 70% ethanol. The remainder can be water. The insecticide formulation can include various additions to the ethanol/water combination.
In another embodiment of the invention, the preferred solvent component comprises a mixture comprising water, ethanol and isopropanol, wherein the final concentration of total alcohol range from 50-80% alcohol, more preferably 65-75% alcohol and most preferably about 69-71% alcohol, with a preferred example 70% alcohol. The remainder can be water. The concentration of ethanol and isopropanol are 25-45% ethanol, 25-45% isopropanol, more preferably 30-40% ethanol, 30-40% isopropanol and most preferably 35% ethanol and 35% isopropanol.
In another embodiment of the invention, the solvent comprises a mixture comprising dipropyleneglycol monomethyl ether (DPM) and water at a concentration range of about 30-70% DPM, more preferably about 45-55% DPM and most preferably about 50% DPM/50% water mixture.
In yet another embodiment of the invention, the preferred solvent is a mixture comprising water, ethanol and DPM at a concentration range of 25-40% ethanol, 25-40% DPM, more preferably 30-35% ethanol, 30-35% DPM and most preferably equal volumes of each component (i.e., 33% ethanol, 33% DPM and 33% water).